This invention relates to improvements in tools particularly suited for use in bending sheet metal and means for and methods of their application enabling a highly advantageous use thereof in press brakes. It features a forming tool having an interchangeable anvil which offers a quick and simple means and method for making a change in the contour of its operating surface. A further feature of the invention is an improved assembly of a forming tool in the nature of a rotary bender wherein the position of the rocker element thereof may be precisely and easily correlated with the thickness of the stock to be worked.
An additional important feature of the invention is the provision of an arrangement, relative positioning and configuration of the operating elements of tooling for rotary bending which permits working of sheet metal in a press brake without whip up of the stock during a forming operation.
The use and application of rotary benders has been generally foreign to a press brake operation. Those practicing in this particular art have deemed it appropriate and have persisted in the use of conventional rigid "V" blocks and conventional punches to produce the particular bend required in sheet stock. In their procedure the operating end of the punch is shaped as closely as possible to the bend required and the stock is presented in a generally horizontal overlying bridging relation to the "V" shaped notch in the associated block. To achieve any real degree of precision in the bending operation the punch or other forming tool applied to the stock must bottom that portion of the stock to which it applies in the notch of the underlying "V" block. This bottoming procedure requires a lot of tonnage to achieve a reasonable result. The tonnage factor can be reduced by using an "air bending" procedure. However, this procedure will not give a consistent result or as good a result as "bottoming" as far as the accuracy of the bend is concerned.
In any case, since one deals with sheets of material which are large and heavy in use of a press brake, whether a bottoming or air bending procedure is utilized, the operation requires, normally, a considerable amount of manpower. Of greater concern is "whip up" of the stock being inherent in the use of either a bottoming or air bending procedure as heretofore practiced. Operators can and have been seriously injured as a result of whip up, so extreme caution must be used in any instance of a press brake operation in accordance with the prior art.
The present invention not only makes the use of rotary benders more feasible in a press brake operation but enables bends to be achieved, consistently, with a high degree of accuracy and requires substantially less tonnage than that required for "bottoming" in the press brake to accomplish a result equal to or better than may be achieved by a conventional bottoming operation such as above described.
The present invention not only solves the above problems but lends additional benefits in the application of its apparatus to a press brake operation.
Of course the invention method and apparatus may be utilized in other than press brakes. However it is particularly described with reference to press brakes because of the important contributions which it lends to this area of industry.
The inventor does not know of any particular prior art which exhibits the specifics of the present invention as herein claimed. However, reference is made to rotary benders having pertinence to this aspect of the present disclosure as being best represented by that shown and described in U.S. Pat. No. 4,002,049 which issued on Jan. 11, 1977.